Liquid electrophotographic printing (“LEP”) is a printing technique that has experienced considerable growth in recent years. LEP stands in contrast to conventional dry electrophotography (or dry EP) printing techniques employed in “laser” printing and xerographic copying. In dry EP, dry toner particles are fixed to the paper being printed at relatively high temperatures at or above 130° C. In LEP, the toner particles are applied to the paper from dispersion in a liquid medium. With LEP printing, the toner particles are fixed to the paper at relatively lower temperatures in the order of from about 45° C. to 95° C.
Thus, for optimum printing, the paper used for the printing application must be receptive to receiving and fixing the LEP toner at these reduced temperatures. In the past, this has required that the paper be specially treated with a coating such as poly(ethyleneimine) in an off-line process after the manufacture of the paper has otherwise been completed. This additional off-line process adds considerable time and expense to the manufacture of papers suitable for LEP printing.
What is needed therefore is a new and improved process for producing a paper suitable for LEP, and which does not require an off-line coating step. There is also a need for a new and improved paper for LEP.